Replicating the flyby sampling of salty ocean world ice grains using impact ionization mass spectrometry

Abstract: The Europa Clipper mission will arrive at the Jovian system in 2030 and analyze ice grains sourced from the icy material on its surface using impact mass spectrometry, which will provide key constraints on Europa's chemical composition and habitability. However, deriving quantitative compositional information from spaceborne impact mass spectra of ice grains has historically proven difficult due to the confounding effects of composition and impact velocity, coupled with difficulties in accelerating ice grains to spacecraft velocities under analogous sampling conditions. Using a novel hypervelocity ice grain acceleration and impact mass spectrometry method, we quantify the degree to which the mass spectra of NaCl-rich ice grains are influenced by chemical composition and impact velocity variations within the flyby velocity ranges planned for the Europa Clipper mission. These results suggest that high-fidelity studies quantifying composition and velocity-related effects in impact mass spectra may be necessary to accurately interpret data collected at Europa and other ocean worlds in the future.